EP3592463A1

EP3592463A1 - Centrifugo-pneumatic switching of liquid

Info

Publication number: EP3592463A1
Application number: EP18708690.5A
Authority: EP
Inventors: Ingmar Schwarz; Nils Paust; Steffen ZEHNLE; Mark Keller; Tobias HUTZENLAUB; Frank Schwemmer
Original assignee: Hann-Schickard-Gesellschaft fuer Angewandte Forschung eV
Current assignee: Hann-Schickard-Gesellschaft fuer Angewandte Forschung eV
Priority date: 2017-03-10
Filing date: 2018-03-05
Publication date: 2020-01-15
Anticipated expiration: 2038-03-05
Also published as: US20190388886A1; WO2018162413A1; CN110650801B; PL3592463T3; DE102017204002B4; EP3592463B1; US11141728B2; DE102017204002A1; CN110650801A; ES2864739T3

Abstract

A fluid module for switching liquid from a liquid retaining region, into which a liquid can be introduced, to downstream fluid structures has at least two fluid paths, which fluidically connect the liquid retaining region with the downstream fluid structures. One of the two fluid paths has a siphon channel. The downstream fluid structures are not deaerated or are only deaerated by a deaeration delay resistance so that when the liquid is introduced into the liquid retaining region, an enclosed gas volume is produced in the downstream fluid structures. By setting the relationship between a centrifugal pressure caused by a rotation of the fluid module and a pneumatic pressure prevailing in the gas volume, the liquid can be retained in the liquid retaining region or be transferred via the siphon channel to the downstream fluid structures, wherein a deaeration takes place via the other fluid path.

Description

Centrifugo-pneumatic switching of liquid

description

The present invention is directed to apparatus and methods for centrifugally-pneumatically switching liquids from a liquid holding area to subsequent fluidic structures utilizing a ratio of centrifugal pressure to pneumatic pressure.

introduction

Centrifugal microfluidics deals with the handling of liquids in the picoliter to milliliter range in rotating systems. Such systems are mostly polymer disposable cartridges used in or in place of centrifuge rotors with the intention of automating laboratory processes. Standard laboratory processes such as pipetting, centrifuging, mixing or aliquoting can be implemented in a microfluidic cartridge. For this purpose, the cartridges contain channels for the fluid guidance, as well as chambers for the collection of liquids. Generally, such structures designed to handle fluids may be referred to as fluidic structures. Generally, such cartridges may be referred to as fluidic modules.

The cartridges are subjected to a predefined sequence of rotational frequencies, the frequency protocol, so that the fluids in the cartridges can be moved by the centrifugal force. Centrifugal microfluidics is mainly used in laboratory analysis and mobile diagnostics. The most common type of cartridge to date is a centrifugal microfluidic disk used in special processing equipment known as "Lab-on-a-disk", "LabDisk", "Lab-on-CD", etc. Other formats, such as microfluidic centrifuge tubes, known as "LabTube", can be used in rotors of existing standard laboratory equipment.

For the use of basic fluid operation in a possible product, the robustness and ease of handling the process is of paramount importance. Furthermore, it is advantageous if the basic operation is realized monolithically, so that no additional components or materials, which are due to material costs or additional Construction and connection technology (assembly) would significantly increase the cost of the cartridge are required.

In particular, the switching of liquids is needed as a fundamental operation for the execution of process chains to separate successive fluidic processing steps from each other. Switching processes are therefore indispensable for the automation of laboratory processes in a centrifugal microfluidic rotor.

An example is the measurement of liquid volumes for the production of aliquots, in which after a measuring step, the liquids are switched to subsequent process steps. Further examples are incubation and mixing processes in which the incubation time or the completion of the mixing process must be achieved before switching on.

An important challenge during the development of cartridges for centrifugal microfluidic fluid handling is the adaptation of the structures involved to the properties of the fluids to be processed and to the interactions of the fluids with the cartridge materials used. This, in particular, provides a need for structures and methods for switching fluids that are largely independent of the properties of the fluids and their interaction with the cartridge material. This includes in particular the following properties of the fluids and cartridge materials: the surface tension of the fluids, their contact angle with the cartridge materials used, the viscosities of the fluids and the chemical composition of the fluids.

Another challenge for the development of microfluidic cartridges lies in the manufacturing requirements. Structures that place high demands on manufacturing tolerances result in higher manufacturing costs and greater risk of cartridge failure during processing. This results in a need for structures and methods for switching fluids, in particular liquids, which are robust in terms of their function against production-related deviations. Furthermore, there is a need for structures that are easily manufacturable by established manufacturing processes - which allow high manufacturing precision. In particular, for the production processes of injection molding and injection compression molding, there is a need for structures and methods for switching fluids which, in contrast, for example, of so-called capillary valves, manage without sharp-edged geometry transitions. In the field of centrifugal microfluidics, a processing protocol generally affects all fluidic structures of a cartridge at the same time. As a result of the increasing integration of sequential or parallel processing steps, this generally results in increasing restrictions on the permissible processing protocols. However, in order to be able to integrate various fluidic operations on a centrifugal microfluidic cartridge, there is a need for structures and methods for switching fluids, for which the exact conditions for the occurrence of the switching operation can be adjusted within a wide range by suitable design.

State of the art

The prior art discloses various ways of switching liquids on centrifugal microfluidic platforms. An overview of active and passive, as well as monolithic and non-monolithic liquid-switching structures and methods is provided by O. Strohmeier et al., "Centrifugal Microfluidic Platforms: Advanced Unit Operations and Applications", Royal Society of Chemistry 2015, Chem. Soc. The following presents further prior art relating to passive monolithic structures and related methods whose switching principle is based inter alia on an interplay between centrifugally induced pressures and pneumatic pressures.

S. Zehnle et. "Pneumatic siphon valving and switching in centrifugal microfluidics controlled by rotational frequency or rotational acceleration", Springer Verlag, Microfluid Nanofluid (2015) 19, pages 1259-1269, describe several structures and associated methods for switching liquids A centrifugal microfluidic platform is used to centrifugally pump liquid from a first, non-vented chamber in a first vacuum valve so that gas in the first chamber expands and creates a negative pressure in the first chamber Since a siphon, whose end is vented, is also branched off from the outlet channel, part of the liquid is also driven into the siphon Fill levels, so that the level in the second Chamber is equal to the level in the siphon. With increasing rotational frequency, both levels increase. If the level in the siphon exceeds the siphon The fluid from the first and second chambers is forced through the siphon and can be collected in a third, vented chamber. In a second configuration of the vacuum valve described is shown that with appropriate dimensioning of the flow resistance between the respective chambers of the siphon apex can be achieved by high spin, but not at low spin. Corresponding valve functions are also described in DE 10 2013 215 002 B3.

In the cited paper by S. Zehnle et al. Further, another valve circuit is described in which liquid is driven centrifugally from a first chamber through an outlet channel into a second chamber and at the same time into a branching siphon. Since in this further valve circuit, the first chamber is vented and the second chamber is not vented, a volume of gas is trapped in the second chamber and compressed when driving the liquid into the second chamber. This volume of gas expands as the speed decreases, driving fluid into the siphon. With high rate of deceleration of the speed and corresponding dimensioning of the flow resistances, sufficient liquid is forced into the siphon to completely fill it so that the liquid from the first and second chambers can be forced through the siphon and collected in a third chamber. This valve function is also described in EP 2 817 519 B1.

From DE 10 2013 203 293 B4 it is further known that such a valve circuit, which is referred to above as a further valve circuit, can optionally be provided with a second siphon to the liquid, depending on the deceleration rate of the rotational speed by one or to pass through both siphons.

All of the valve circuits described in the aforementioned document by S. Zehnle have in common that the end of the siphon through which the fluid is driven is vented. Thus, the third chamber, which serves only as a collecting chamber, vented and not coupled to another fluidic element. It has the function as a collecting chamber beyond any other fluidic functions and can not influence the valve functions described by any type of sizing.

D. Mark et al., "Aliquoting on the centrifugal microfluidic platform based on centrifugal-pneumatic valves", Springer Verlag, Microfluid Nanofluid (201 1) 10, pages 1279-1288, describes a structure for aliquoting liquids the liquid through a supply channel sequentially into a series of measuring channels, in which the liquid is held during a Aliquotiervorgangs by so-called Zentrifugo- pneumatic valves. After completion of the Aliquotiervorgangs the Zentrifugo-pneumatic valves between the measuring channels and connected to the measuring channels, radially outermost chambers are switched by increasing the rotational frequency, and transferred the liquids respectively in the radially outer chambers. The principle of operation of the centrifugal-pneumatic valves described consists of two complementary effects. The first effect is that the liquid closes the connecting channel between the measuring channel and subsequent non-ventilated target chamber during filling of the respective measuring channel and thereby causes the centrifugally induced transfer of liquid from the measuring finger into the target chamber to a compression of the gas present therein. The resulting pneumatic overpressure in the target chamber counteracts further flow of the liquid into the target chamber. The second effect is that the connecting channel between the measuring channel and the target chamber at the opening to the target chamber is a capillary valve, which counteracts the advancement of the liquid in the target chamber. The sum of the two effects gives the principle of operation of the centrifugal-pneumatic valve. By increasing the rotation frequency, both effects can be overcome, so that the liquid is transferred into the target chamber. Corresponding centrifugal-pneumatic valves are described in DE 10 2008 003 979 B3 as well as in D. Mark, "Centrifugo-pneumatic valve for metering highly highly-balanced liquids on centrifugal microfluidic patforms", Lab Chip, 2009, 9, p. 3599-3603, described.

Such centrifugal pneumatic valves only allow the compression of a small gas volume through the connecting channel between the measuring channel and the target structure before liquid enters the target chamber. As a result, the switching frequency is structurally limited to low frequencies. At the same time, there is a dependence of the switching frequency on the liquid properties, since the capillary valve effect, which plays a role for the centrifugal-pneumatic valve, depends on the surface tension and the contact angles between the liquid and the cartridge material. Furthermore, if necessary, the requirement of a sharp-edged transition of the connecting channel to the target chamber arises from the described capillary valve portion of the centrifugal pneumatic valve, which is accompanied by additional expenditure for the production.

F. Schwemmer et.al., "Centrifugo-pneumatic multi-liquid aliquoting - parallel aliquoting and combination of multiple liquids in centrifugal microfluidics", Royal Society of Chemistry 2015, Lab Chip, 2015, 15, pages 3250 - 3258, describe structures that consist of a high fluid resistance inlet channel, a measuring chamber, a pressure chamber connected to the measuring chamber via a connecting channel, and a low-fluid resistance outlet channel connected to the measuring chamber , The structures allow the metering and subsequent switching of liquid volumes. The sequence of the measuring and switching process is as follows: First, the liquid to be metered is passed at high rotational frequency through the inlet channel into the measuring chamber until it is completely filled. Thereafter, the radially inwardly connected connecting channel fills to the pressure chamber and excess liquid is fed into the pressure chamber, which represents a trap for them, so that the liquid can not leave the pressure chamber. The from the time of entry of the liquid into the measuring chamber to displaced gas volume in the measuring chamber and the pressure chamber leads to a pneumatic pressure increase in the pressure chamber. After completion of the filling of the structure through the inlet channel, in a second step, the liquid is switched by reducing the rotational frequency in subsequent fluidic structures. This is achieved because the centrifugal pressure in the outlet channel falls below the pneumatic overpressure in the pressure chamber and therefore the liquid is transferred from the pneumatic overpressure and other pressures occurring substantially into the outlet channel. The selected fluidic resistances ensure that the transfer takes place essentially in the outlet channel and not back into the inlet channel. The structures may have a siphon, which ensures during a measuring step that the liquid is not yet switched into a collection chamber. In structures in which the collection chamber is located radially further inward than the measuring chamber, the siphon can be omitted. A corresponding aliquoting is also described in WO 2015/049112 A1.

Due to the switching principle, such a centrifugal-pneumatic aliquoting is suitable only for process chains in which can be switched by reducing the rotational frequency or should. In addition, a minimum rate of deceleration must be achieved to transfer the fluid to a target volume, thereby limiting the usable processing equipment. If it is necessary to switch by increasing the rotational frequency, since processes must take place before switching at a low rotational frequency, centrifugal-pneumatic aliquoting can likewise not be used. Furthermore, centrifugal-pneumatic aliquoting requires additional space for the pressure chamber, which may be lost for the introduction of structures for other operations on the cartridge. Of the The need for strong differences in the fluidic resistance between inlet and outlet channels leads to additional requirements for the production, since high fluidic resistances are achieved by small channel cross-sections, which thereby make high demands on the manufacturing tolerances.

Wisam Al-Faqheri et. al., "Development of a Passive Liquid Valve (PLV) Utilizing a Pressure Equilibrium Phenomenon on the Centrifugal Microfluidic Platform," Sensors 2015, 15, pp. 4658-4676, describe switching fluid as a function of fluid acting on a fluid in an inlet chamber Centrifugal pressure, acting on the liquid in the inlet chamber capillary pressure and acting on a liquid in a venting chamber centrifugal pressure. Air is trapped between the fluids in the inlet chamber and the venting chamber. By increasing the rotational speed, a negative pressure generated in the inlet chamber or an overpressure generated in the deaeration chamber is overcome, thereby to convey liquid from the inlet chamber through a fluid channel into a target chamber.

Description of the invention

The object of the invention is to provide a fluidic module for switching fluids which can be monolithically integrated and easily manufactured, largely fluid and material properties independent and adaptable to a wide range of processing conditions, as well as devices with such a fluidic module and method comprising such a fluidic module use, create.

Embodiments of the present invention relate to fluidic modules, devices, and methods for retaining and selectively switching fluids in centrifugal microfluidic cartridges.

Exemplary embodiments provide a fluidic module for switching liquid from a liquid holding region into downstream fluidic structures, comprising: a liquid holding region, into which a liquid can be introduced, at least two fluid paths, which fluidly connect the liquid holding region to downstream fluidic structures, wherein at least a first fluid path of the two fluid paths has a siphon channel, wherein a siphon apex of the siphon channel is radially within a radially outermost position of the liquid holding region, wherein the downstream fluidic structures are not vented or vented only via a venting delay resistor when the Liquid is introduced into the liquid holding area, so that in the downstream fluidic an enclosed gas volume or vented only via a vent delay resistance gas volume is formed when the liquid is introduced into the liquid-holding area, and by a ratio of one by a rotation of the Fluidic module caused centrifugal pressure and prevailing in the gas volume pneumatic pressure is at least temporarily prevented that the liquid passes through the fluid paths in the downstream fluidic structures, wherein a change in the ratio of the centrifugal pressure to the pneumatic duck can be caused that the liquid passes at least partially through the first fluid path in the downstream fluidic and the gas volume is at least partially vented through the second fluid path of the two fluid paths in the liquid-holding region.

Embodiments of the invention are based on the recognition that it is possible on a centrifugally microfluidic platform, using appropriate fluidic structures, to fill a liquid holding region that may be centrifugally induced, a pneumatic differential pressure to ambient pressure in downstream (subsequent) fluidic structures. and the connecting fluid paths between liquid holding region and subsequent fluidic structures, by which the liquid can be maintained in the liquid holding region under suitable processing conditions, until, induced by a suitable change in the processing conditions, the liquid can be further transferred into the subsequent fluidic structures. During this liquid transfer into the downstream fluidic structures through one of the fluid paths, a venting of the downstream fluidic structures can take place through the other of the fluid paths. By appropriate processing conditions, such as rotational speed and / or temperature, while the ratio between pneumatic pressure and centrifugal pressure can be adjusted or changed to achieve the described functionalities. Embodiments continue to be based on the finding that during a, for example, centrifugally induced filling operation of the liquid holding region, gas can be displaced into the downstream fluidic structures through the connecting fluid paths between the liquid holding region and the downstream fluidic structures, and further that the displaced gas volume is merely through the liquid volume is limited, can be chosen arbitrarily by suitable design of the connecting fluid paths, whereby the processing conditions under which the liquid is held in the liquid holding region, as well as the processing conditions under which the liquid is switched into the downstream fluidic structures, in a wide range and largely irrespective of liquid properties or cartridge material properties.

In embodiments, the liquid can be introduced by a centrifugal pressure caused by a rotation of the fluidic module via a radially sloping inlet channel into a fluid chamber of the liquid-holding region. As a result, the rotation used during introduction of the liquid into the liquid holding region can achieve the ratio between centrifugal pressure and pneumatic pressure, which prevents liquid from entering the downstream fluidic structures. In embodiments, the inlet channel may be further connected to an upstream fluid chamber.

In embodiments, a second fluid path of the two fluid paths is a vent channel for the downstream fluidic structures, which is closed by the liquid when the liquid is introduced into the liquid holding area. Thus, it is possible to close a venting channel for the downstream fluidic structures simultaneously with the introduction of a liquid volume into the liquid-holding region, so that no separate means are required for this purpose.

In embodiments, the first fluid path opens in a radially outer region or at a radially outer end into the liquid-holding region, so that the liquid-holding region at least up to the region in which the first fluid path opens into the liquid-holding region via the first Fluid path is emptied. This makes it possible to empty a large part of the liquid or the entire liquid from the liquid holding area. In embodiments, the liquid holding region has a first fluid chamber, wherein the first fluid path opens into the first fluid chamber in a radially outer region of the first fluid chamber or at a radially outer end of the first fluid chamber. In such embodiments, the first fluid chamber may be deflated or vented only via a venting delay resistor when the fluid is introduced into the fluid retaining region, such that a volume of gas trapped in the first fluid chamber and the downstream fluidic structures is merely vented gas volume created by a venting delay resistor occurs when the liquid is introduced into the liquid holding region.

In exemplary embodiments, the liquid-holding region has a first fluid chamber and a second fluid chamber into which a liquid can be introduced by a centrifugal pressure caused by rotation of the fluidic module, wherein the first fluid path opens into the first fluid chamber and the second fluid path opens into the second fluid chamber, and wherein the second fluid path is closable by a liquid introduced into the second fluid chamber. In such embodiments, the first fluid chamber and the second fluid chamber may be fluidly interconnected via a connection channel having its mouth radially inward of the first fluid chamber than a radially outer end of the first fluid chamber such that fluid from the first fluid chamber overflows into the second fluid chamber when the level of liquid in the first fluid chamber reaches the mouth, and closes the second fluid path opening into the second fluid chamber. Such embodiments may allow first liquid is held in the first fluid chamber and only in the downstream Fluidikstrukturen is switched by the addition of further liquid, which may be a different liquid from the first liquid.

In embodiments, the second fluid path has a siphon channel. This allows increased flexibility with regard to the opening of the second fluid path into the liquid holding region and increased flexibility with regard to the processing conditions, as this can prevent liquid from entering the downstream fluidic structures via the second fluid path. For example, in such embodiments, the second fluid path may open into the liquid holding region in a radially outer region of the liquid holding region. In such embodiments, a vertex of the siphon channel of the second fluid path may be located radially further inward than a vertex of the siphon channel of the first fluid path. In embodiments, the second fluid path has a siphon channel and a fluid intermediate chamber is disposed in the second fluid path between the apex of the siphon channel of the second fluid path and the mouth of the second fluid path in the liquid holding area, wherein the intermediate fluid chamber is at least partially filled with the liquid when the liquid is introduced into the liquid holding area. The intermediate fluid chamber may have a smaller volume than a first fluid chamber of the liquid holding portion. In embodiments, a radially outer end of the intermediate fluid chamber is located radially outward of the siphon apex of the first fluid path. The first intermediate fluid chamber allows a greater amount of fluid to enter the second fluid path before its meniscus reaches the apex of the siphon channel of the second fluid path.

In exemplary embodiments, the downstream fluidic structures have at least one downstream fluid chamber into which the first fluid path and the second fluid path open. Alternatively, the first and the second fluid path may also lead into different chambers of the downstream fluidic structures, as long as it is ensured that a pressure equalization between the mouths of the first and the second fluid path into the downstream fluidic structures during the fluid holding phase. Thus, it is possible to collect the switched liquid in the downstream fluidic structures. The first fluid path can open radially further out into the downstream fluid chamber than the second fluid path. This allows the mouth of the second fluid path to remain in the downstream fluid chamber for venting as the fluid passes into the downstream fluidic structures. The downstream fluid chamber may be a first downstream fluid chamber, the downstream fluidic structures may have a second downstream fluid chamber, which is fluidly connected via at least one third fluid path with the first downstream fluid chamber. Thus, it is possible to implement fluidic structures that enable cascaded switching.

In embodiments, the downstream fluidic structures may include a first downstream fluid chamber and a second downstream fluid chamber, the first downstream fluid chamber being fluidly connected to the second downstream fluid chamber via a third fluid path and a fourth fluid path, wherein at least the third fluid path includes a siphon channel third fluid path and the fourth fluid path are closed by the liquid when the liquid by changing the ratio of the centrifugal pressure to the pneumatic Pressure passes through the first fluid path in the first downstream fluid chamber of the downstream fluidic, whereby in the second downstream fluid chamber an enclosed gas volume or vented only via a vent delay resistance gas volume is formed and by a ratio of the centrifugal pressure and in the gas volume in the second downstream Fluid chamber prevailing pneumatic pressure is at least temporarily prevented that the liquid passes through the fluid paths (in particular the third and fourth fluid path) in the second downstream fluid chamber, and wherein caused by a change in the ratio of the centrifugal pressure to the pneumatic duck in the second downstream fluid chamber can that the liquid passes through the third fluid path in the second downstream fluidic chamber and the gas volume from the second downstream fluid chamber through the fourth fluid path to partially vented into the liquid holding area. Thus, it is possible to implement fluidic structures that enable cascaded switching.

Embodiments provide an apparatus for switching fluid from a fluid holding area to downstream fluidic structures having a fluidic module as described herein, driving means configured to impart rotation to the fluidic module, and actuator configured. to effect the change of the ratio of the centrifugal pressure to the pneumatic duck. In embodiments, the actuator is configured to increase or decrease the rotational speed of the fluidic module to effect the change in the ratio of the centrifugal pressure to the pneumatic duck. In embodiments, the actuator is designed to reduce the pneumatic pressure in the downstream fluidic structures by reducing the temperature in the downstream fluidic structures and / or by increasing the volume of the downstream fluidic structures and / or reducing the amount of gas in the downstream fluidic structures.

Embodiments provide a method of switching fluid from a fluid holding area to downstream fluidic structures using a fluidic module as described herein, having the following features:

Introducing at least one liquid into the liquid-holding region and holding the liquid in the liquid-holding region by rotating the fluidic module, so that the liquid in a by the centrifugal pressure and the pneumatic pressure dominant Neten quasi-stationary equilibrium is maintained in the liquid holding area; and

Changing the ratio of the centrifugal pressure to the pneumatic duck to at least partially transfer the liquid through the first fluid path into the downstream fluidic structures and to vent the volume of gas at least partially into the fluid holding region through the second fluid path of the two fluid paths.

In embodiments, holding the liquid in the liquid holding region comprises generating a pneumatic overpressure in the downstream fluidic structures prior to the initiation of the transfer. In embodiments, changing the ratio of the centrifugal pressure to the pneumatic duck includes increasing the rotational speed of the fluidic module, increasing the hydrostatic head of the fluid, and / or decreasing the pneumatic pressure. In embodiments, holding the liquid in the liquid holding region includes creating a negative pressure in the downstream fluidic structures to adjust and hold menisci in the liquid holding region and the first and second fluid paths without passing the liquid through the first fluid path into the downstream one Fluidic structures to transfer, wherein changing the ratio of the centrifugal pressure to the pneumatic pressure, a reduction in the rotational speed of the fluidic module and / or reducing the pneumatic pressure in the downstream fluidic structures and / or increasing the hydrostatic height of the liquid in the liquid holding area.

In embodiments, changing the ratio includes decreasing the pneumatic pressure by decreasing the temperature in the downstream fluidic structures, increasing the volume of the downstream fluidic structures, and / or reducing the amount of gas in the downstream fluidic structures.

In embodiments, during the transfer of the liquid through the first fluid path, the second fluid path is not completely filled with liquid. In embodiments, the molar amount of the gas in the downstream fluidic structures is not changed while the liquid is held in the liquid holding area.

Embodiments of the invention are explained below with reference to the accompanying drawings. Show it: 1 is a schematic representation of fluidic structures according to an embodiment for overpressure-based switching;

2A to 2E are schematic diagrams for explaining the operation of the

Embodiment of Fig. 1;

3A to 3D are schematic representations of fluidic structures according to an embodiment in which the downstream fluidic structures have a fluid receiving chamber and a further chamber;

4A to 4D are schematic representations of fluidic structures according to an embodiment, in which a fluid intermediate chamber is arranged in a fluid path between the liquid Haitebereich and downstream Fluidikstrukturen;

5A to 5D are schematic representations of fluidic structures according to an embodiment with changed connection positions of the fluid paths;

6 is a schematic representation of fluidic structures according to an exemplary embodiment with cascaded structures;

7A to 7E are schematic diagrams for explaining the operation of the

Embodiment of Fig. 6;

8A to 8E are schematic representations of fluidic structures according to an embodiment for the vacuum-based switching;

9 is a schematic representation of fluidic structures according to an embodiment with a liquid-Haitebereich having two fluid chambers.

10A to 10D are schematic diagrams for explaining the operation of the

Embodiment of Fig. 9; 11A to 1E are schematic diagrams for explaining the operation of the embodiment of Figure 9 when using two liquids ..;

12A and 12B are schematic side views for explaining embodiments of devices for switching liquids; and

13A and 13B are schematic plan views of embodiments of Fluidikmo- modules.

Embodiments of the invention relate to microfluidic structures for centrifuge-pneumatic switching and to methods for centrifugal-pneumatic switching, in particular for the centrifugo-pneumatic switching of liquids from a liquid-holding region, which may have a first chamber, into subsequent or downstream fluidic structures. Subsequent or subsequent (these terms are used interchangeably herein) fluidic structures herein are referred to as fluidic structures, such as e.g. Channels or chambers, understood to enter the fluid during handling thereof from upstream or upstream (these terms being used interchangeably herein) fluidic structures. In this case, the microfluidic structures may have a first chamber, which is connected to the following fluidic structures via at least two fluid paths, wherein at least the fluid path through which the fluid is transferred when switching into the subsequent fluidic structures is configured in the shape of a siphon. The structures and the method may be designed such that the relevant pressures in the direction or opposite to the filling of the path for the liquid transfer by centrifugal pressures or pneumatic pressures are given. Switching in which centrifugal pressures and pneumatic pressures dominate other pressures can be referred to as centrifugal-pneumatic switching.

In embodiments, pneumatic overpressures and / or negative pressures may be used.

In the case of the use of overpressures, gas is displaced into the subsequent fluidic structures during the filling of the first chamber with a liquid, as a result of which a pneumatic overpressure is created in these. This pneumatic overpressure can be selected within a wide range by means of suitable design and determines, with otherwise unchanged processing conditions, significantly for the switching of the liquid necessary rotation frequency (switching frequency). In this case, prior to the switching operation, the centrifugally induced pressure in the first chamber is less than the pressure required in order to wet against the pneumatic overpressure in the subsequent fluidic structures the apex of the siphon-shaped channel, through which the liquid is transferred into the subsequent fluidic structures during the switching process , This represents a (quasi-static) equilibrium state. By increasing the rotational frequency of the cartridge over the switching frequency, the centrifugal pressure can be increased above the switching pressure, whereby the siphon is wetted and the transfer of the liquid into the subsequent fluidic structures is initiated. Alternatively, or in combination, the hydrostatic height of the fluid may also be increased to initiate fluid transfer, for example by adding additional fluid into the fluid holding region via upstream fluidic structures.

In the case of the use of negative pressure for the switching principle, in embodiments the subsequent fluidic structures can first be heated, so that a gas contained in them expands and part of this gas can escape. As a result, when liquid is transferred into the liquid holding region and the rotational frequency is increased, the liquid in the fluid communication paths may be at approximately the same radial height as in the liquid holding region. When the temperature in the subsequent fluidic structures is reduced, a negative pressure results which acts in the direction of the subsequent fluidic structures. However, since the connection paths are siphon-shaped, this increases the hydrostatic height in the connection paths, so that the centrifugal force in this case counteracts further filling of the connection paths. This is the (quasistatic) equilibrium state under negative pressure conditions. By further increasing the negative pressure and / or by reducing the centrifugal pressure, a switching process can then be initiated.

Embodiments illustrate methods of retaining liquids and initiating the switching process by other changes in processing conditions along with the structures associated therewith. Common to all structures and methods is that during transfer, the second fluid interconnect between liquid holding area and downstream fluidics structures may be utilized Allow gas from the downstream fluidic in the liquid holding area or a fluid chamber of the liquid-holding area to escape or flow, which can reduce the pneumatic pressure difference to the downstream fluidic structures. In the following some definitions are given for designations used herein.

By hydrostatic head is meant the radial distance between two points in a centrifugal cartridge, if at both points there is liquid of a continuous quantity of liquid. Hydrostatic pressure is the centrifugal force-induced pressure difference between two points due to the hydrostatic head between them. The effective fluidic resistance of a microfluidic structure is the quotient of the pressure that drives a fluid through a microfluidic structure and the resulting fluid flow through the microfluidic structure. Aliquoting is the division of a liquid volume into several separate individual volumes, so-called aliquots.

Metering is the measurement of a defined volume of liquid from a larger volume of liquid to understand. Switching frequency is understood to be the rotational frequency of a microfluidic cartridge, beyond which a transfer process of a liquid from a first structure to a second structure begins. A siphon channel is to be understood as a microfluidic channel or a section of a microfluidic channel in a centrifugally microfluidic cartridge in which the inlet and outlet of the channel are located at a greater distance from the center of rotation than an intermediate region of the channel. A siphon apex is understood to mean the area of a siphon channel in a microfluidic cartridge with a minimum distance from the center of rotation.

By a venting delay resistance is meant the fluidic resistance through which a fluidic structure in which a pneumatic differential pressure to the ambient pressure prevails, is vented. The fluidic resistance is at least so high that the reduction of the differential pressure to half of it, taking into account only the venting by the fluidic resistance takes at least 0.5 s. This applies at any time during the venting.

If in embodiments a venting delay resistor is provided for the downstream fluidic structures, the time profile of the pressure drop in these fluidic structures can be determined, for example, by filling the liquid holding area at a constant temperature with liquid under centrifugation and the hydrostatic height between an upstream chamber and a fluid Chamber in which the liquid is held in the liquid-retaining structures, in quasi-stationary equilibrium by a suitable camera system (eg with stroboscopic exposure) is recorded. The rotational frequency and the hydrostatic head result in the pneumatic overpressure existing in the following structures. Therefore, the degradation rate of the overpressure can also be determined from this image information, resulting in the size of the venting delay resistance. In other embodiments, such as switching at negative pressure, the method can be analogously used by liquid is filled at a certain frequency and start temperature and then a defined rapid cooling is generated. The development of the hydrostatic height in the connection paths and their rate of degradation results in turn in the size of the venting delay resistance.

All fluids that are in a quasi-static fluid state change their position within the cartridge in which they are located, depending on the processing conditions. That All fluid transport processes between fluidic structures which take place under constant processing conditions have been completed. Further, liquid transport processes that are a consequence of changes in processing conditions, at any time during the change in processing conditions, within a maximum of 1 second on their respective half as soon as the change in the processing conditions are stopped abruptly.

A fluid guide path is to be understood as meaning a fluidic structure through which fluid flows from the fluid-holding region into one or more subsequent fluidic structures during the execution of the method according to the invention. A gas guidance path is to be understood as meaning an IV fluidic structure through which gas exchange takes place between the subsequent fluidic structures and the fluid holding area during the execution of the method according to the invention. A fluid receiving volume is understood to mean a fluidic fluid structure which provides a volume into which fluid is transferred after initiation of the switching process according to the invention.

By a microfluidic cartridge is meant herein an apparatus, such as a fluidic module, having microfluidic structures that facilitate liquid handling as described herein. A centrifugal microfluidic cartridge means a corresponding cartridge which is subjected to rotation. can, for example in the form of an insertable into a body of revolution fluidic or a body of revolution.

As used herein, a fluid channel means a structure whose length dimension is greater from a fluid inlet to a fluid outlet, for example more than 5 times or more than 10 times greater than the dimension defining the flow area or define. Thus, a fluid channel has a flow resistance for flowing through it from the fluid inlet to the fluid outlet. In contrast, a fluid chamber herein is a chamber which has dimensions such that, as it flows through the chamber, there is a negligible flow resistance compared to connected channels, which may be, for example, 1/100 or 1/1000 of the flow resistance of the channel structure with the smallest flow resistance connected to the chamber ,

Before embodiments of the invention are explained in more detail, it should first be pointed out that examples of the invention can be found in particular in the field of centrifugal microfluidics, which involves the processing of liquids in the picoliter to milliliter range. Accordingly, the fluidic structures can have suitable dimensions in the micrometer range for handling corresponding volumes of liquid. In particular, embodiments of the invention can be applied to centrifugal microfluidic systems, as known for example under the name "Lab-on-a-Disk".

As used herein, the term radial is meant to be radial with respect to the center of rotation about which the fluidic module or body is rotatable. Thus, in the centrifugal field, a radial direction is radially sloping away from the center of rotation and a radial direction toward the center of rotation is radially increasing. A fluid channel, the beginning of which is closer to the center of rotation than the end, is thus radially sloping, while a fluid channel, the beginning of which is farther from the center of rotation than its end, is radially increasing. A channel which has a radially rising section thus has directional components which rise radially or extend radially inwards. It is clear that such a channel does not have to run exactly along a radial line, but can run at an angle to the radial line or bent. Referring to Figs. 12A, 12B, 13A and 13B, examples of centrifugal microfluidic systems and fluidic modules will now be described in which the invention may be used.

FIG. 12A shows a device with a fluidic module in the form of a rotary body 10, which has a substrate 12 and a cover 14. 13A shows schematically a plan view of the rotary body 10. The substrate 12 and the cover 14 may be circular in plan view, with a central opening 15, in which a center of rotation R is arranged and via which the rotary body 10 via a conventional fastening means 16 at a rotating part 18 of a drive device 20 may be attached. The rotating part 18 is rotatably supported on a stationary part 22 of the drive device 20. The drive device 20 may be, for example, a conventional adjustable-speed centrifuge or a CD or DVD drive. A control device 24 may be provided, which is designed to control the drive device 20 in order to act on the rotation body 10 with rotations with different rotational frequencies. The controller 24 may be configured to execute a frequency protocol to achieve the functionalities described herein. As will be appreciated by those skilled in the art, the controller 24 may be implemented by, for example, a suitably programmed computing device, a microprocessor, or a custom integrated circuit. The controller 24 may further be configured to control the drive device 20 upon manual inputs by a user to effect the required rotations of the rotating body. In either case, the controller 24 may be configured to control the drive device 20 to apply the required rotational frequencies to the fluidic module to implement embodiments of the invention as described herein. As drive device 20, a conventional centrifuge with only one direction of rotation can be used.

The rotary body 10 has the fluidic structures described herein. Corresponding fluidic structures are indicated purely schematically in FIG. 13A by trapezoidal regions 28a to 28d. For example, a plurality of fluidic structures may be juxtaposed in the azimuthal direction, as shown in FIG. 13A, to facilitate parallel handling of multiple fluids. The fluidic structures may be formed by cavities and channels in the lid 14, the substrate 12 or in the substrate 12 and the lid 14. In embodiments, for example, fluidic structures can be formed in the substrate 12, while filling openings and venting can be formed. openings are formed in the lid 14. In embodiments, the patterned substrate (including fill openings and vents) is located at the top and the lid is located at the bottom.

In an alternative embodiment shown in FIG. 12B, fluidic modules 32 are inserted into a rotor 30 and together with the rotor 30 form the rotary body 10. FIG. 13B schematically shows a plan view of a corresponding fluidic module. The fluidic modules 32 may each have a substrate and a lid, in which corresponding fluidic structures may again be formed. The rotational body 10 formed by the rotor 30 and the fluidic modules 32 in turn can be acted upon by a drive device 20, which is controlled by the control device 24, with a rotation.

In FIGS. 12 and 13, a center of rotation about which the fluidic module or the rotational body is rotatable is denoted by R.

In embodiments of the invention, the fluidic module or body having the fluidic structures may be formed of any suitable material, for example, a plastic such as PMMA (polymethylmethacrylate), PC (polycarbonate), PVC (polyvinylchloride), or PDMS (polydimethylsiloxane), glass or the like. The rotary body 10 may be considered as a centrifugal microfluidic platform.

As will be explained below, in embodiments, the control means 24 is an actuator which can adjust the rotational speed of the drive means to initiate fluid transfer, ie to cause the ratio of the centrifugal pressure to the pneumatic pressure to cause switching of the fluid becomes. In embodiments of the invention, the actuator may additionally include one or more heaters and / or coolers to control the temperature of the fluidic structures to initiate fluid transfer. For example, one or more temperature control elements 40 (heating element and / or cooling element) may be integrated into the rotary body, as shown in FIGS. 12A and 12B. Alternatively or additionally, one or more external temperature control elements 42 can be provided, via which the temperature of the fluidic structures can be adjusted. The external temperature control elements can be designed, for example, to the temperature of the environment and thus also to control the fluidic module. The controller may be configured to control the temperature control elements 40, 42 so that in such embodiments, the actuator may include the controller 24 and the temperature controls.

With reference to FIGS. 1 to 11, embodiments of fluidic modules (microfluidic cartridges) and fluidic structures formed therein will now be described.

1 shows schematically fluidic structures formed in a fluidic module 50. The fluidic module 50 is rotatable about a center of rotation R. The fluidic structures have a liquid holding region, which has a first chamber 52. The first chamber 52 is connected to preceding fluidic structures which have an upstream chamber 54, which is connected to the first chamber 52 via a radially sloping connection channel 56. The connecting channel 56 opens in a radially outer region 57, for example, the radially outer end, in the first chamber 52. About the upstream chamber and the connecting channel 56, the first chamber is centrifugally filled. It should be noted at this point that the first chamber may also be filled in a manner other than centrifugal, wherein only after the filling, the fluidic module is subjected to a rotation in order to achieve the equilibrium between centrifugal pressure and pneumatic pressure.

The fluidic module 50 further includes subsequent fluidic structures having a fluid chamber 58 as the fluid receiving volume and two fluid paths 60, 62 fluidly connecting the first chamber 52 to the fluid chamber 58. The fluid path 62 has a siphon channel whose siphon apex 64 lies radially within the radially outermost position of the first chamber 52. The subsequent fluidic structures in the form of the fluid chamber 58 are either not vented or may be vented via a venting delay resistor 66 which satisfies the above definition. Such a venting delay resistor 66 may optionally be provided in all of the embodiments described herein without each requiring separate mention.

In the embodiment shown, the first fluid path 60 between the first chamber 52 and the subsequent fluidic structure 58 consists of a channel extending from a radially inner region of the first chamber 52, for example, from the radially innermost point 68 of the first chamber 52, to a radially inner region the subsequent fluid chamber mer 58, for example, to the radially innermost point 70 of the subsequent fluid chamber 58 leads. The second fluid path 62 between the first chamber 52 and the subsequent fluid chamber 58 is connected to the first chamber 52 in a radially outer region, for example at the radially outermost point 72 and leads via the siphon vertex 64 to a radially outer region, for example radially outermost point 74, the subsequent fluid chamber 58.

Between the respective mouth of the two fluid paths 60 and 62 in the first fluid chamber 52 and the respective mouth into the subsequent fluid chamber 58 is a radial gradient.

Embodiments of a method according to the invention include introducing at least one liquid into a first chamber of the liquid-holding region. This introduction can be effected by a centrifugally induced transfer of a liquid into the first chamber 52. Subsequently, a centrifugally-pneumatically induced retention of the liquid in the liquid-holding region, for example, the first chamber 52, take place. Subsequently, a switching of the liquid in the subsequent fluidic structures, for example, the subsequent fluid chamber 58, take place. During the switching operation, at least a portion of the liquid is transferred from the liquid holding region (e.g., first chamber 52) into the subsequent fluidic structures (e.g., fluid chamber 58) through at least one fluid path (e.g., fluid path 62). Fluid paths through which liquid is transferred during the switching process are referred to below as fluid guide paths. By means of at least one further fluid path (eg fluid path 62) between the fluid holding region (eg first chamber 52) and the subsequent fluid structures (eg fluid chamber 58), gas (usually air) can be withdrawn from the subsequent fluid structures back into the fluid during the switching process. Holding area to be transferred. Fluid paths that permit this are referred to below as gas routing paths.

An exemplary embodiment of such a method will be described below with reference to the operation of the fluidic module 50 shown in FIG. 1 with reference to FIGS. 2A to 2E. FIGS. 2A to 2E show fluid operating states of the embodiment shown in FIG. 1 during the execution of the method. For the sake of clarity, the respective reference symbols of the fluidic structures are omitted in FIGS. 2A to 2E. In a first state, shown in Fig. 2A, liquid 80 is in the first chamber 52 upstream chamber 54 and in the connecting channel 56 between the upstream chamber 54 and the first chamber 52. In this case, a part of the upstream chamber 54 is radially closer to the center of rotation R than the siphon vertex 64 of the fluid guide channel. The liquid can be introduced, for example, via an inlet opening or via further upstream fluidic structures into the upstream chamber 54 and the connecting channel 56. The introduced liquid 80 encloses in the first chamber 52, the fluid paths 60 and 62 and the downstream fluid chamber 58 an air volume that is not vented (or vented only via a venting delay resistor). In other words, the fluid path 60, which constitutes a venting channel, is also closed to the atmosphere by the liquid 80 in the liquid holding region.

As shown in FIG. 2B, subsequently, the liquid 80 is centrifugally induced to transfer from the upstream chamber 54 into the first chamber 52, compressing the gas in the first chamber 52, the subsequent fluid structures 58, and the communication paths 60, 62 the first chamber 52 is not vented in this operating state or vented only via a venting delay resistor. The upstream chamber 54 may be vented, so that in the same atmospheric pressure p ₀ can prevail. Gas is preferably transferred via the gas guide path 60 into the subsequent fluid structures 58. The fluid paths 60, 62 between the first chamber 52 and subsequent fluidic structures are connected to one another via the subsequent fluidic structures, so that it is ensured that the same pneumatic overpressure prevails in the fluid paths. Simultaneously with the filling of the first chamber 52 and the liquid guide path 62 can be filled with liquid, but not up to the siphon vertex 64th

The resulting pneumatic overpressure Δρ in the first chamber 52 and the subsequent fluid structures 58 counteracts the further centrifugally induced filling of the first chamber 52 and the filling of the fluid guide channel 62, so that the Siphonscheitei 64 is not wetted in the fluid guide channel 62 and the liquid is in the first chamber 52 and in the first chamber 52 upstream chamber 54 is retained. Thus, these fluidic structures constitute a liquid holding area.

The retention of the liquid in the liquid holding area is achieved by 1) the liquid transfer into the first chamber 52 reduces the hydrostatic height between the upstream chamber 54 and the first chamber 52, which reduces the centrifugal pressure acting in the direction of filling the first chamber 52, and

2) at the same time the pneumatic overpressure in the subsequent Fluidik- structures with progressive filling of the first chamber 52 increases, so that at a suitable rotational frequency of the cartridge equilibrium between the forces acting in the direction of filling the liquid guide path 62 pressures and the filling of the liquid guide path counteracting Press adjusts. The corresponding suitable rotational frequency can readily be determined depending on the geometries and liquid quantities used.

In all the embodiments described herein, with a suitable choice of the geometries of the chambers and the fluid guide channel can be achieved that centrifugal pressure and pneumatic overpressure over other pressure sources such. capillary pressure, taking into account any fluid properties and cartridge material properties. This means that these other pressure sources are not able to cause a switching-triggering deviation from the Befüllzustand the liquid guide path, which results in the sole consideration of the balance of pneumatic pressure and centrifugal pressure. This equilibrium is also realized in accordance with the invention if, by slight targeted variations of the processing conditions, the pressures involved are varied continuously, leaving the qualitative state of retention of the liquid in the liquid holding region (e.g., the first chamber). In other words, while maintaining the liquid in a quasi-steady state equilibrium, a slight variation of the processing conditions may occur without initiating the switching operation.

Starting from the equilibrium state shown in Fig. 2B, the switching operation can be achieved by increasing the centrifugal pressure on the switching frequency or the centrifugal switching pressure. This can e.g. be achieved by

1) the rotation frequency is increased or

2) the hydrostatic height is increased by adding liquid in the preceding fluidic structures. By increasing the centrifugal pressure, further liquid from chamber 54 upstream of first chamber 52 is transferred to the first chamber so that the level in first chamber 52 and liquid guide path 62 increases and siphon vertex 64 of fluid guide channel 62 is filled, as in FIG Fig. 2C is shown.

Alternatively, the switching operation can be achieved by reducing the pneumatic overpressure in the subsequent fluidic structures, so that liquid is induced pneumatically induced from the upstream chamber 54 into the first chamber 52 and the siphon apex 64 of the liquid guide path 62 is filled at a constant rotational frequency. The reduction of the pneumatic overpressure may e.g. by reducing the temperature in the subsequent fluidic structures, by increasing the volume of the subsequent fluidic structures, or by reducing the amount of gas in the subsequent fluidic structures. The latter can be done via a venting delay resistor, for example the venting delay resistor 66 shown in FIG.

As a result of one of the described triggering process condition variations, or a combination thereof, the radially outwardly extending portion of the siphoned channel 64 fills in the liquid guide path 62, thereby increasing the hydrostatic head in that channel. The centrifugal pressure resulting from the hydrostatic head between the first chamber 52 and subsequent fluidic structures results in fluid transfer from the first chamber 52 to the subsequent fluidic structures, as shown in Figures 2C through 2E.

During the liquid transfer, gas from the subsequent fluidic structures is transferred via the at least one gas guide path 60 into the first chamber 52, which counteracts the build-up of an additional pneumatic overpressure in the sequence of fluid transfer into the subsequent fluidic structures, see FIG. 2D. Thereby, a complete transfer of the liquid from the first chamber 52 into the subsequent fluidic structures at a fixed rotational frequency above the switching frequency can be achieved, as shown in Fig. 2E. After complete transfer of the liquid into the downstream fluid chamber, the fluidic structures may be at atmospheric pressure po. The switching pressure and the associated rotation frequency of the cartridge (switching frequency) can be selected by a suitable choice of the positions and geometries of the chambers and the fluid guide paths in a wide range.

In the following, further embodiments will be explained in more detail. Due to the dependencies between structure and method, the particular features and the peculiarities of the method resulting from the features are specified together for the exemplary embodiments. Where Bescheibungsteile would be repeated in the description of the various embodiments, these are partially omitted, so that description parts can apply across embodiments. Although the described embodiments in part only each show a fluid path between preceding fluidic structures and the first chamber and only one liquid guide path and a gas guide path between the first chamber and the subsequent fluidic structures, this does not limit the number of possible connection paths between the fluidic structures within the scope of the invention and merely serves to simplify the description of the embodiments.

FIG. 3A schematically shows an exemplary embodiment of fluidic structures of a fluidic module 50 in which the complete first fluid chamber 52 is filled with fluid 80 in the quasi-stationary equilibrium state, which is shown in FIG. 3B.

In the embodiment shown in FIG. 3A, both the liquid guide path 62 and the gas guide path 60 have a siphon-shaped channel. Again, an upstream chamber 54 via a connecting channel 56 which opens into a radially outer end 90 of the upstream chamber 54, fluidly connected to the first chamber 52. The liquid guide path 62 and the gas guide path 60 may open into the first chamber 52 and the downstream chamber 58 as in the embodiment described with reference to FIG. The siphon apex 64 of the liquid guide path 62 is disposed radially within the radially innermost point of the first chamber, and a siphon apex 92 of the siphon channel of the gas guide path 60 may preferably be radially inwardly of the siphon apex 64 of the liquid guide path 62. The following fluidic structures in this embodiment, in addition to the downstream fluid chamber 58, which is a fluid receiving volume and a fluid receiving chamber, another, separate volume 94 on. The point of connection of the gas guide path 60 to the liquid receiving volume 58 (in the embodiment shown, the radially innermost Preferably, the point of fluid receiving volume 58) may be closer to the center of rotation R of the cartridge than the radially outermost point of the fluid receiving volume 58, thereby wetting the port 70 of the gas routing path 60 with the fluid 80 transferred during the shift under the influence of the transfer during the transfer Prevent centrifugal force. The optional volume 94, which is separate from the liquid receiving volume 52, specifically increases the volume of the subsequent fluidic structures, as a result of which the pneumatic overpressure in the subsequent fluidic structures can be reduced when carrying out the method according to the invention. In the embodiment shown, the additional volume 94 is coupled to the gas routing path 60 via a fluid path 96. The fluid path 96 opens at an orifice 98 into the gas guide path 60 and at an orifice 100 into the additional volume 94.

In the embodiment shown in FIGS. 3A to 3D, the foregoing fluidic structures comprise the chamber 54, the volume of which preferably comprises a fraction of the volume of the first chamber 52, and which is connected to the first chamber 52 through the fluid path 56, its connection point 90 to the upstream chamber 54 closer to the center of rotation R of the cartridge than the apex of the siphon 64 in the liquid guide path 62. In alternative embodiments, the volume of the chamber 54 may be greater than the volume of the first chamber 52. The chamber 54 may in turn be vented and at atmospheric pressure. The connection point 57 of the fluid connection path 56 between the preceding chamber 54 and the first chamber 52 can lie at any desired point of the first chamber 52 and need not be arranged in a radially outer region thereof.

The embodiment of a pneumatic counter-pressure siphon valve shown in FIGS. 3A to 3D is designed to compress the full volume of the first chamber. 3B shows an operating state in which there is a balance between pneumatic overpressure in the subsequent fluidic structures and the pressures in the direction of the filling of the subsequent fluidic structures. 3C shows an operating state in which the liquid is transferred from the first chamber into the subsequent fluidic structures, and FIG. 3D shows an operating state after completion of the liquid transfer.

In operation, liquid 80 is introduced into the first fluid chamber 52 via the upstream fluidic structures. The fluidic structures are designed such that the first te fluid chamber 52 is completely filled with the liquid 80. The introduced liquid encloses a gas volume in the downstream fluidic structures. In Fig. 3B, the corresponding state is shown, in which the liquid 80 is retained in the first chamber 52. The cartridge or the fluidic module can be in rotation with a rotational frequency ωι. There is liquid in the chamber 54 of the preceding fluidic structures, the first fluid chamber 52, and the radially inward portions of the fluid guide path 62 and the gas guide path 60. Due to the hydrostatic head difference between the fluid meniscus in the preceding fluidic structures and menisci 102, 104 in the fluid communication paths 60 and 62, a centrifugal pressure acts in the direction of filling the fluid communication paths 60 and 62. The pressures that counteract the filling of the siphon with a greater radial distance from the center of rotation R (ie the siphon in Flüssigkeitssführungspfad 62) (pneumatic overpressure Δρ and possibly others such as pressures, eg capillary pressure) are in equilibrium with the pressures acting in the direction of filling this siphon (centrifugal pressure and possibly other). As a result, the liquid is in a quasi-steady state equilibrium.

The location of the liquid menisci 102, 104 in the fluid communication paths 60, 62 makes it possible to utilize the described structure to measure the amount of fluid in the first chamber 52 and fluid communication paths, with high accuracy of the metered volume.

Starting from the state shown in FIG. 3B, increasing the rotation frequency to a value> which leads to an increase in the centrifugal pressure in the direction of the subsequent fluidic structures, or else by filling the backpressure in the subsequent fluidic structures, the siphon apex 64 of the liquid guide path 62 can be filled. The liquid may then be sequentially transferred from the first chamber 52 into the liquid receiving volume 58 by the acting centrifugal force, as shown in Fig. 3C. During this process, the gas is transferred from the liquid receiving chamber 58 via the gas guide path 60 into the first chamber 52, whereby an increase in the pneumatic overpressure in the liquid receiving chamber 58 is counteracted. During this liquid transfer, the gas volume initially remains trapped in the downstream fluidic structures and the first chamber, so that in each case a pneumatic overpressure .DELTA.p prevails, as indicated in Fig. 3C. After completion of the liquid transfer is a compensation of the pneumatic overpressure of the subsequent fluidic and the first chamber with the preceding fluidic structures via the connecting channel 56 instead. After fluid transfer, the fluidic structures are at atmospheric pressure po, as shown in FIG. 3D.

An embodiment in which a compression chamber volume is provided in the gas guide path will be described below with reference to FIGS. 4A to 4D.

4A shows fluidic structures formed in a fluidic module 50, which have an inlet channel 110, a first fluid chamber 52, a liquid guide path 62, a gas guide path 60, a downstream fluid chamber 58 and a volume chamber 112 arranged in the gas guide path 60. The inlet channel 110 may in turn be fluidly coupled to an upstream chamber (not shown in FIG. 4A). Thus, in turn, a fluidic connection to previous fluidic structures may be provided through the channel 110 having its point of attachment to the first fluid chamber 52 radially inward of the siphon apex 64 of the fluid guide path 62. Downstream Fluidikstrukturen are in turn formed by the downstream fluid chamber 58, which is a fluid receiving chamber.

The liquid receiving chamber 58 is connected to the gas guide path 60 at a mouth point. The orifice point is preferably not at the radially outermost position of the fluid receiving chamber 58, for example, in a radially inner portion thereof or at the radially innermost position 70. The fluid receiving chamber 58 is also fluidically connected to the fluid guide path 62, preferably radially outward of the port position 72 between the fluid guide path 62 and the first fluid chamber 52. The fluid guide path 62 may open at a radially outer position, for example at the radially outermost position 74, into the fluid receiving chamber 58.

In the embodiment shown in FIG. 4A, the liquid receiving path 62 opens into the first fluid chamber 52 in a radially outer region, such as the radially outermost position 72, and the gas guide path 60 also opens at a radially outer position, such as the radially outermost position 116 of FIG In FIG. 4A, the left-hand area of the first fluid chamber 52, into the first fluid chamber 52. The gas-guidance path 60 has a siphon channel, the siphon apex 92 of which lies radially inside the siphon apex 64 of the liquid guide path 62. The volume chamber 112, too may be referred to as a partial compression chamber is disposed in the radially rising portion of the siphon channel of the gas guide path 60, wherein the gas guide path 60 opens into the partial compression chamber 112 at mouth points 118 and 120. The partial compression chamber 112 is preferably located at a greater radial distance from the center of rotation than the siphon vertex 64 of the liquid guide path 62. The partial compression chamber 112 may be connected to the first fluid chamber 52 through a portion of the gas routing path 60, the junction at which that portion of the gas routing path is in the sub-compression chamber 112 opens, preferably radially further away from the center of rotation than the siphon vertex 64 of the fluid routing path 62. The orifice point 120 can then be connected to the downstream fluidic structures via the siphon channel of the gas routing path 60 having the siphon apex 92.

An exemplary embodiment of a method according to the invention using fluidic structures, as shown in FIG. 4A, will now be described with reference to FIGS. 4B to 4D. First, fluid from pre-switched fluidic structures (not shown) centrifugally induced may be transferred into the first fluid chamber 52 via the inlet channel 110. Under the influence of the centrifugal force, the liquid 80 fills the first chamber from the radially outer side toward the radially inner side. Thereby, the fluid paths 60 and 62 connecting the first fluid chamber 52 to the subsequent fluidic structures, such as the downstream fluid chamber 58, are filled and gas (typically air) trapped by the fluid 80 in the downstream fluidic structures and fluid communication paths 60 and 62 , The increase in the hydrostatic head between the liquid meniscus 122 in the first fluid chamber 52 and the menisci 102, 104 in the fluid communication paths 60 and 62 transfers liquid into the subcompression chamber 112 under the influence of centrifugal force, thereby injecting the gas present therein into the subsequent fluidic structures is displaced. As a result, a pneumatic overpressure Δρ is generated in the latter, which counteracts further filling of the fluid connection paths 60 and 62. A balance is formed between the pressures toward and against the filling of the fluid paths 60 and 62 in which the siphon apex 64 of the liquid guide path 62 is not wetted and the meniscus 122 of the liquid in the first fluid chamber 52 radially within the siphon apex 64 of the liquid guide path 62 is located. This operating state is shown in FIG. 4B. The liquid 80 encloses a gas volume in the fluid paths 60, 62 and the downstream fluidic structures 58, in which the pneumatic overpressure Δρ is generated. Because the first Fluid chamber 52 is vented, the area of the first fluid chamber 52 above the liquid meniscus 122 is at atmospheric pressure po.

By a suitable choice of the partial compression volume 112 and the volumes of the downstream fluidic structures, the pneumatic overpressure Δρ which prevails in equilibrium in the following fluidic structures can be selected largely freely.

By increasing the rotational frequency, starting from the operating state shown in FIG. 4B, the centrifugal pressure in the direction of filling the liquid guide path 62 can be increased, whereby the siphon vertex 64 of the liquid guide path 62 fills and a centrifugally induced transfer of the liquid into the subsequent fluidic structures 58 is set in motion. In embodiments, the partial compression chamber 112 has a smaller volume of fluid than the first fluid chamber 52. Due to the fluid transfer from the first fluid chamber 52 into the downstream fluidic structures via the fluid guide path 62, an additional pneumatic overpressure is built up in the trapped volume of the subsequent fluid structures, resulting in transfer of fluid Liquid from the partial compression chamber 112 into the first fluid chamber 52 leads. As soon as the pneumatic overpressure Δρ in the downstream fluidic structures exceeds the hydrostatic pressure acting on the gas guide path 60 in the first fluid chamber 52, gas is transferred from the subsequent fluidic structures 58 via the gas guide path 60 into the first fluid chamber 52 and through the fluid Operating state shown in Fig. 4C. The operating state after completion of the liquid transfer is shown in Fig. 4D.

Referring now to Figs. 5A to 5D, an embodiment with connection position variations of the fluid paths will now be described. The fluidic structures shown in FIG. 5A demonstrate a possible range of possible variations in the choice of port locations between the first fluid chamber 52 and the fluid communication paths 60 and 62, as well as the design of the gas routing path 60 and the ports between the fluid communication paths 60 and 62 and FIG downstream fluidic structures 58.

In embodiments, the port position 130 between the preceding fluidic structures (eg, the inlet port 110 and the upstream fluid chamber 54) and the first fluid chamber 52 may be at a freely selectable position of the first fluid chamber 52. The same applies to connection positions 132, 134 of the connection tion paths 60, 62 between the first fluid chamber 52 and subsequent fluidic structures 58 to the first fluid chamber 52 to. In the event that a partial compression chamber 112 is present in the gas guide path 60, the connection points 132 and 118 of the connections between the first fluid chamber 52 and the partial compression chamber 112 and the connection points 120, 136 between the partial compression chamber 112 and the subsequent fluidic structures 58 can also be freely selected. Preferably, the mouth point 136 of the gas guide path 60 is in the downstream fluid chamber 58, that is, the liquid target volume, not at the radially outermost position of the liquid target volume. Furthermore, the connection position 138 of the Flüssigkeitsführungs- path 62 can be freely selected in the downstream fluid chamber 58. The connection position 134 is preferably located in a radially outer region of the first fluid chamber 52, since the first fluid chamber 52 can be emptied only up to this connection position above the liquid guide path 62.

An exemplary embodiment of a method according to the invention will be explained with reference to FIGS. 5B to 5D by means of the operation using the fluidic structures shown in FIG. 5A. First, liquid from the upstream fluidic structures, such as upstream chamber 54, is centrifugally induced to be transferred to first fluid chamber 52 and associated fluid communication paths 60 and 62. In this case, the level of the first fluid chamber 52 increases continuously in the radial direction from the radially outermost point of the same to radially further inward positions. During the filling process, the gas in the first fluid chamber 52 is displaced by the inflowing fluid 80, thereby transferring gas into the non-fluid wetted ports of the fluid communication paths 60, 62 between the first fluid chamber 52 and the downstream fluidic structures. This results during the filling of the first fluid chamber 52, a pressure equalization between the first fluid chamber 52 and the subsequent fluidic structures, as long as the level in the first fluid chamber 52 is radially outside the radially innermost connection point.

As shown in FIG. 5A, the terminal position 134 of the liquid guide path 62 to the first fluid chamber 52 may be closer to the rotation center R than the terminal position 132 of the gas guide path 60. Further, more fluid may be transferred into the first fluid chamber 52 than through the first fluid chamber 52 and the fluid connection paths 60, 62 to the radial position of the radially inner connection point (of the connection point 134 in the embodiment shown in FIG. 5A). Example) can be included. In this case, furthermore, the first fluid chamber 52 can be designed without further vents, so that in the gas volume trapped by the liquid 80, with continued transfer of liquid from the upstream fluidic structures into the first fluid chamber 52, a pneumatic overpressure Δρι can be established is not identical to the pneumatic overpressure Δρ in the subsequent fluidic structures. During the filling of the first fluid chamber 52, furthermore, the partial compression chamber 112 in the gas guide path 60 can be filled with liquid, whereby gas is transferred into the subsequent fluidic structures. By selecting the connection point 120 of the fluid path 60 between the sub-compression chamber 112 and the downstream fluidic structures 58 at a position radially outwardly of the innermost point of the sub-compression chamber 112, compression of gas in the sub-compression chamber may be analogous to the described processes in the first fluid chamber 112 occur as soon as the liquid level in the sub-compression chamber 112 is radially within the radially innermost connection point to the sub-compression chamber 112.

By a corresponding filling of the liquid-holding portion, which has the first chamber 52 and the partial compression chamber 1 12, a state of equilibrium can be achieved, in which the meniscus 104 of the liquid is in the radially inwardly extending portion of the siphon-shaped portion of the liquid guide path 62, and the pressures acting in the direction of wetting of the siphon vertex 64 (centrifugal pressure and possibly other pressures, such as the overpressure Δρι) are in equilibrium with the pressures acting against the wetting (the pneumatic overpressure in the subsequent fluidic structures and possibly other pressures). This operating state is shown in Fig. 5B.

Starting from the state shown in FIG. 5B, by increasing the centrifugal pressure or decreasing the pneumatic back pressure, wetting of the siphon vertex 64 of the liquid guide path 62 can be achieved, whereby a liquid transfer from the first fluid chamber 52 to the liquid target volume 58 of FIG downstream fluidic structures is initiated. As a result, the level in the first fluid chamber 52 may drop below the connection point 130 of the inlet channel 110 into the first fluid chamber 52, so that venting of the first fluid chamber 52 to atmospheric pressure p ₀ takes place. As was explained above with reference to the embodiment described in FIGS. 4A to 4D, as soon as the pneumatic overpressure in the downstream fluidic structures becomes hydrostatic Pressure acting on the gas guide path 60 in the first fluid chamber 52, gas from the subsequent fluidic structures is transferred via the gas guide path into the first fluid chamber and through the liquid, this operating state again being shown in FIG. 5C.

In the embodiment shown in FIGS. 5A to 5D, after the connection point 134 between the liquid guide path 62 and the first fluid chamber 52 is radially inside the radially outermost point of the first fluid chamber 52, the transfer may stop as soon as the fluid meniscus 122 in the first fluid chamber 52 reaches the radial position of the connection point 134. This may result in the retention of fluid in the first fluid chamber 52, as shown in FIG. 5D, resulting in the possibility of mixing them in the first fluid chamber 52 by multiple use of the same fluidic structures with different fluids. This may also be used to create dilution series if, in a first step, a volume of liquid to be diluted defined by the fluidic structure remains in the first fluid chamber after the transfer step, and in subsequent steps the dilution liquid through the preceding fluidic structures into the first fluid chamber transferred and mixed with the liquid to be diluted. The downstream fluidic structures can be given for this purpose by a cascading of the structures described, that is, by radially outwardly offset instances of the structure described.

6 shows an exemplary embodiment of cascaded fluidic structures in a fluidic module 50. The cascaded fluidic structures essentially represent a combination of the embodiments described with reference to FIGS. 3A to 3D and FIGS. 4A to 4D. The structure of the upstream fluid chamber 54, of the connection channel 56, FIG. The first fluid chamber 52, the gas guide path 60, the Flüssigkeitsfüh- tion path 62 and the downstream fluid chamber 58 corresponds to the above-described reference to FIGS. 3A to 3D described structure of the corresponding structures. These elements form a first switching structure in the cascaded fluidic structures shown in FIG. A gas guide path 160, a liquid guide path 162 and a further downstream fluid chamber 158 form a second switching structure. As shown in FIG. 6, a venting delay resistor 66 may optionally be provided. In the gas guide path 160, an intermediate compression chamber 112 is arranged. The structure of the gas guide path 160, the intermediate compression chamber 1 12 and the liquid guide path 162 may be substantially the structure of the gas guide path 60, the intermediate compression chamber 112 and the gas guide path 62 described above with reference to FIG. 4A. As shown in FIG. 6, the liquid guide path 162 can open into the downstream fluid chamber 58 in a radially outer region, for example the radially outermost position, and can open into the downstream fluid chamber 158 in a radially outer region, for example the radially outermost position , The gas guide path 160 may open into the downstream fluid chamber 58 in a radially outer region, for example the radially outermost position, and may open into the downstream fluid chamber 158 in a radially inner region, for example the radially innermost position. The fluid paths 160 and 162 have a total of a radial gradient, that is, the mouth of the same in the fluid chamber 158 is located radially further outward than the mouth thereof in the fluid chamber 58th

The fluidic structures shown in FIG. 6 thus represent two cascaded switching structures, wherein the fluid chamber 58 for the first switching structure represents a downstream fluidic structure and represents a liquid holding area for the second switching structure. With reference to FIGS. 7A to 7E, an embodiment of a method according to the invention for the cascaded switching of liquids is described below. FIGS. 7A to 7E show an illustration of the fluidic processes during the process of cascading fluid switching using the venting delay resistor 66. FIG. 7A shows fluid 80 in the first fluid chamber 52 of the first switching structure. FIG. 7B shows a fluid transfer into the liquid-targeting chamber 58 of the first switching structure, which at the same time represents the first fluid chamber of the second switching structure. Fig. 7C shows the final state of the first switching operation, which simultaneously represents the equilibrium state before the initiation of the second switching operation. Fig. 7D shows the transfer of the liquid into the liquid-targeting chamber 158 of the second switching structure. Fig. 7E shows the final state after completion of the second liquid transfer.

Referring to Figs. 7A to 7E, a second switching operation may be implemented due to the presence of a development delay resistor.

First, liquid is centrifugally induced induced in the first fluid chamber 52 and the fluid connection paths 60, 62 analogously to the method described above, and the gas present in these is displaced into the subsequent fluidic structures, whereby in this a pneumatic overpressure arises, which counteracts the further filling and thus the wetting of the siphon vertex 64 in the liquid guide channel 62. The downstream fluidic structures have the downstream fluid chamber 58, the fluid paths 160, 162 and the downstream fluid chamber 158. After the first fluid chamber 52 has preferably been completely filled with liquid, the quasi-static state shown in Fig. 7A is reached. The pressures acting in the direction of wetting the siphon vertex 64 of the liquid guide path 62 are in quasi-static equilibrium with the pressures counteracting this wetting, with the pneumatic overpressure in the downstream fluidic structures slowly degrading via the venting delay resistor 66. As a result, with constant or decreasing rotational frequency due to the reduction of the pneumatic back pressure, the wetting of the siphon vertex 64 of the liquid guide path 62 and, associated therewith, the initiation of the transfer process into the downstream fluid chamber 58, ie the first liquid target volume, can be achieved. This operating state is shown in Fig. 7B. Alternatively or in combination, the other process condition changes described herein for initiation of the switching process may also be used, for example increasing the rotational frequency or reducing the pneumatic overpressure, for example by reducing the temperature.

During the first transfer process, as described above with reference to FIGS. 3A to 3D, gas is vented via the gas guide path 60 through the first fluid chamber 52. During this first transfer process, overpressure which is still present in the subsequent fluidic structures of the second switching structure can still be partially retained from the first gas displacement process, since complete venting does not have to occur during the transfer. This is illustrated in FIG. 7C by the pneumatic overpressure Δρ remaining in the downstream fluid chamber 158. In the centrifugally induced first transfer process, similarly to the processes described above with reference to FIGS. 4A to 4D, the first fluid chamber of the second switching structure, that is, the fluid chamber 58 and the partial compression chamber 112 of the second gas guide path 160 are filled with liquid and the above Gas contained therein displaced in the downstream fluidic 158. The resulting pneumatic overpressure Δρ leads to the quasi-static state shown in FIG. 7C, in which the pressures opposing the wetting of the siphon vertex 164 of the liquid guide path 162 are in quasi-static equilibrium with those in the direction of wetting. Due to the continual In addition, slow venting of the pneumatic overpressure in the subsequent fluidic structures 158 of the second switching structure (due to the venting delay resistor 66) can in turn achieve wetting of the siphon apex 164 of the liquid guide path 162 at a constant or decreasing rotational frequency, thereby providing second fluid transfer to the downstream fluid chamber 158 , So the liquid target structure of the second switching structure can be achieved. During this liquid transfer, gas may be vented from the fluid chamber 158 via the gas guide path 160 into the fluid chamber 58. The operating state of the liquid transfer is shown in Fig. 7D. The operating state after completion of the second liquid transfer into the liquid chamber 158 is shown in Figure 10E.

With reference to FIGS. 6 to 7E, an embodiment for cascaded switching structures has thus been described. It does not require a separate explanation that also other embodiments described herein can be cascaded, wherein in each case all process condition changes described herein can be used to initiate the respective switching process. Although in the described example a cascaded structure using a vent delay resistor as the actuator is described, it is not necessarily required.

Generally, according to the present invention, liquid transfer is effected by changing the ratio of the centrifugal pressure to the pneumatic pressure. The change of this ratio can be done in different ways. In embodiments, the ratio can be changed by increasing a rotational speed of the fluidic module. For this purpose, for example, a drive device, by means of which the fluidic module is set in rotation, can be correspondingly controlled by means of a corresponding control device. Alternatively or additionally, it is possible to reduce the pneumatic pressure to change the ratio. For this purpose, a venting delay resistor may be provided, which may be considered as an actuator designed to reduce the pneumatic pressure. Alternatively or in combination, the pneumatic pressure may be reduced by controlling, in particular reducing, the temperature of the trapped gas volume. This can be done either by controlling the temperature of the entire fluidic module or at least parts of the fluidic module in which the gas volume is enclosed. For this purpose, as described above Referring to Figs. 12A and 12B, temperature control elements may be provided. Alternatively or in combination, a reduction of the pneumatic pressure can be achieved by increasing the volume of the downstream fluidic structures. For example, the downstream fluidic structures may have one or more fluid chambers whose volume is adjustable.

Referring to Figs. 8A to 8E, an embodiment in which a negative pressure is used in the downstream fluidic structures, that is, an embodiment of the present invention will be described below. a reduction of the pressure in the downstream fluidic structures below the ambient pressure. In such embodiments, switching may occur using temperature and / or centrifugal pressure changes.

As already described, a temperature-controlled reduction of the pressure in the subsequent fluidic structures, which serves to initiate the transfer of liquid from the first fluid chamber into the liquid target volume, can be achieved by a reduction of the temperature of the gas in the subsequent fluidic structures.

As shown in FIG. 8A, the fluidic structures formed in a fluidic module 50 have an inlet channel 200 connecting a first fluid chamber 202 to preceding fluidic structures (not shown). The first fluid chamber 202 may be vented via a fluid path 204. The first fluid chamber 202 is connected via a first fluid path 206 and a second fluid path 208 to downstream fluidic structures 210, which have a fluid receiving chamber. The first fluid path 206 has a siphon channel with a siphon vertex 212. The second fluid path 208 also has a siphon channel in the embodiment shown, the siphon apex 214 of which is located radially further inward than the siphon apex 212 of the first fluid path 206. The first fluid path 206 represents a liquid guide path, and the second fluid path 214 provides a gas guide path The fluid communication paths 206 and 208 need not include any further chambers. The liquid guide path 212 is connected to the first fluid chamber in a radially outer region, preferably at the radially outermost position. The gas guide path 208 is connected in a region of the first fluid chamber 202 with the latter, which is wetted with liquid when filling the first fluid chamber 202. Such a filling of the first fluid chamber can be effected centrifugally induced via the inlet channel 200. Possible positions for the orifices of the fluid paths 206 and 208 in the first fluid chamber 202 result from the chamber geometry and the amounts of liquid used in the process. Of the The siphon apex 212 of the liquid guide path 206 is preferably radially within the position reached during operation by the meniscus of the liquid in the first fluid chamber, particularly during a first processing step during which liquid in the first fluid chamber 202 representing a liquid holding region. is held. As shown in FIG. 8A, the gas guidance path 208 can open into the downstream fluidic structures 210 in a radially inner region, and the liquid guidance path 206 can open into the downstream fluidic structures 210 in a radially outer region.

The fluidic structures shown in Figure 8A illustrate fluidic structures for vacuum-based centrifugal-pneumatic vent-siphon valve switching, as will become apparent from the following description of an embodiment of a method according to the invention using the fluidic structures shown in Figure 8A.

In a first step, liquid is transferred from upstream fluidic structures (not shown) centrifugally induced through the inlet channel 200 into the first fluid chamber 202. In this case, liquid is also transferred into the radially inwardly extending regions of the siphon-shaped connection paths 206, 208 between the first fluid chamber 202 and the subsequent fluidic structures 210. From the time at which the connection point of the last of the connection paths 206, 208 is wetted, the further liquid flowing into the connection paths displaces the gas contained in the connection paths into the downstream fluidic structures, resulting in overpressure at constant temperature in the subsequent fluidic structures, as shown in FIG. 8B is shown. This excess pressure as the difference to the atmospheric pressure may be a small fraction of the atmospheric pressure, so that there is a negligible overpressure during the introduction.

Starting from the operating state shown in FIG. 8B, cooling of the subsequent fluidic structures 210 can be achieved at a preferably constant rotational speed, for example by a reduction in the ambient temperature or by cooling elements in contact with the cartridge, whereby a negative pressure results in the subsequent fluidic structures, as indicated in Fig. 8C. As a result, depending on the processing conditions (eg rotational frequency, geometry of the chambers and channels, start and end temperature in the subsequent fluidic structures, etc.), a new hydrostatic altitude arises between the menisci 102, 104 in the fluid communication paths 206, 208 and Meniscus 122 of the fluid in the first fluid chamber 202 leading to a new equilibrium between the pressures in the direction of filling the siphon vertex 212 of the liquid guide path 206 (in this embodiment, the pneumatic negative pressure in the subsequent fluidic structures and possibly other subordinate pressures) and the pressures against this filling (at this embodiment, the centrifugal pressure due to the adjusting hydrostatic height and possibly other subordinate pressures), as shown in Fig. 8C. Starting from the operating state present under these process conditions, wetting of the siphon apex 212 of the liquid guide path 206 can be achieved in a subsequent step by reducing the centrifugal pressure, for example by reducing the rotational frequency or by further reducing the pressure in the subsequent fluidic structures, for example by further reducing the temperature Alternatively, and in addition, liquid may be added to the fluid chamber 202 to wet the siphon apex, whereby the fill level may be raised above the siphon apex. As part of the liquid transfer, the transferred liquid can lead to a compression of the gas present in the subsequent fluidic structures 210, so that an overpressure can arise therein, which leads to a transfer of gas from the downstream fluidic structures via the gas guide path 208 into the first fluid chamber 202 as shown in Fig. 8D. In the following, the first fluid chamber 202 completely empties via the liquid guide path 206 into the downstream fluidic structures, as shown in FIG. 8E.

In the embodiments described so far, the liquid-holding region has a first fluid chamber. In alternative embodiments, the fluid retaining region may include a plurality of fluid chambers, which may or may not be connected via one or more fluid channels.

An embodiment in which the liquid holding portion has a plurality of fluid chambers and in which switching can be effected by temperature-controlled pressure reduction will be explained below with reference to FIG. 9.

Again, corresponding fluidic structures are formed in a fluidic module 50. The fluidic structures have upstream fluidic structures, a liquid holding region and downstream fluidic structures. The liquid holding region has a first fluid chamber 300 and a second fluid chamber 302. The first fluid chamber 300 and the second fluid chamber 302 are fluidly connected via a radially sloping connection channel 304. The upstream fluidic structures have an upstream fluid chamber 306 which may have in a radially outer region of the same chamber segments 306a and 306b with respect to a center of rotation R, which allow a measurement of liquid volumes. The chamber segment 306 a is fluidically connected to the first fluid chamber 300 via a fluid channel 308, and the chamber segment 306 b is fluidically connected to the second fluid chamber 302 via a fluid channel 310. Another inlet channel 312 may be fluidly connected to the first fluid chamber 300. Another inlet channel / vent channel 314 may be fluidly connected to the second fluid chamber 302. A vent 316 is shown schematically in FIG. Further, another fill / vent passage 318 may be provided.

It should be noted that the upstream fluidic structures in the embodiment shown in Fig. 9 could also consist of only one inlet channel, which is fluidly connected to the first fluid chamber 300 and which allows filling of the first fluid chamber 300, for example, a centrifugally induced filling from an inlet chamber fluidly connected to the corresponding inlet channel.

As shown in FIG. 9, the first fluid chamber 300 is connected via a fluid guidance path 320 to downstream fluidic structures 322 in the form of a downstream fluid chamber. The second fluid chamber 302 is connected to the downstream fluidic structure 322 via a gas guide path 324. The liquid guide path 320 has a siphon channel with a siphon vertex 326. In the embodiment shown, the gas routing path 324 also has a siphon channel with a siphon vertex 328. The achievable hydrostatic head difference between the meniscus in chamber 302 and the siphon apex 328 is preferably higher than the hydrostatic head difference between the meniscus in chamber 300 and the siphon apex 326 to overcome.

The liquid guide path 320 opens into the first fluid chamber 300 in a radially outer region, preferably at a radially outer end. The gas guide path 328 opens into the second fluid chamber 302 in a radially outer region, preferably at a radially outer end may be configured such that when filling the same with a first volume of liquid, the downstream fluidic structures 322 remains vented via the gas guide path 324 to the second fluid chamber 302. This operating state, in which a first liquid volume is introduced into the first fluid chamber 300, 380 is shown in Fig. 10A. Changes in the temperature and / or rotational frequency can be further carried out without the liquid being switched into the downstream fluidic structures 322. In the event that capillary forces are negligible, the liquid is stored in this state, so to speak, in the fluid chamber 300.

If further liquid volume is now introduced into the first fluid chamber 300, for example via the channels 308 and / or 312, the volume of liquid in the first fluid chamber 300 increases until excess volume through the connecting channel 304, which constitutes an overflow, into the second fluid chamber 302 flows. For this purpose, the mouth of the connecting channel into the first fluid chamber 300 is located radially farther inward than a radially outer end of the first fluid chamber 300. The excess fluid volume 382 overflowing into the second fluid chamber 302 closes the gas guide path 324 which is in the radially outer end second fluid chamber 302 opens, airtight. Thus, both fluid paths 320 and 324 are now hermetically sealed to the downstream fluidic structures, after the liquid guide path 320 has already been hermetically sealed when introducing the liquid volume 380 into the first fluid chamber 300. This operating state is shown in FIG. 10B.

From this operating state, as described above with reference to FIGS. 8A to 8E, by reducing the temperature and correspondingly reducing the pressure, a negative pressure can be generated in the downstream fluidic structures 322, as shown in FIG. 10C. As also described with reference to FIGS. 8A to 8E, subsequently, by reducing the centrifugal pressure and / or by further reducing the pressure in the subsequent fluidic structures, the liquid can be caused to be transferred via the liquid guide path 320 into the downstream fluidic structures 322, as shown in Fig. 10D. In this case, the siphon channel of the liquid guide path 320 is configured such that, for example, when reducing the temperature and thereby reducing the pressure induced only this siphon, so that preferably only the liquid from the first fluid chamber 300 and not the liquid from the second fluid chamber 302 transfers becomes. A potential overpressure in the downstream fluidic structures 322 due to the transfer of the liquid from the first fluid chamber 300 forces the liquid from the gas guide channel 324 back into the second fluid chamber 302, wherein air through the second fluid chamber 302 in the form of rising through the liquid bubbles can give way. Thus, all of the liquid from the first fluid chamber 300 can be transferred to the downstream fluidic structures 322.

Under strong negative pressure, the siphon channels of both the liquid guide path 320 and the gas guide path 324 can also be filled with liquid. As a result, both the fluid in the first fluid chamber 300 and the fluid in the second fluid chamber 302 would then be at least partially transferred. As a result of the subsequent transfer of the fluid through the fluid guidance path into the chamber 322, the negative pressure in the chamber 322 can be at least partially compensated. By transferring sufficiently large amounts of liquid, an overpressure can be generated in addition to the compensation of the negative pressure, which leads to a reversal of the flow direction of the liquid within one of the siphon channels, in the embodiment shown in the gas guide channel 324, and then to a phase change to gas, whereby gas from the subsequent fluidic structures 322 is vented into the chamber 302.

One embodiment, as described with reference to FIGS. 9 to 10D, may be useful for metering a fluid prior to switching to a predefined volume. Liquid volumes below the target volume are not switched.

The fluidic structures described with reference to FIG. 9 may also be used to add a second liquid, as will be explained below with reference to FIGS. 11A to 11E.

FIG. 11A corresponds to the operating state from FIG. 10A, in which a first liquid volume 380 is introduced into the first fluid chamber 300 and is quasi stored in the first fluid chamber 300. If a second liquid then flows through the inlet channel 310 into the second fluid chamber 302, the following fluidic structures 302 are hermetically sealed. For this purpose, the second liquid can flow either exclusively into the second fluid chamber 302 via the channel 310, or divided into the first fluid chamber 300 and the second fluid chamber 302 via the channels 308 and 310. The corresponding volumes supplied for this purpose in the chamber segments 306a and 306b of the upstream fluid chamber 306 are measured, as shown in Fig. 1 B is shown. When the second liquid flows into the first fluid chamber 300 and the second fluid chamber 302, the first and second fluids in the first fluid chamber 300 may be mixed. As shown in FIGS. 11C-11E, subsequently, the liquid may be transferred from the first fluid chamber 300 to the downstream fluidic structures 322 as described above with reference to FIGS. 8A-8E and 10A-10D. In particular, the liquid can be transferred by reducing the temperature and corresponding reduction of the pressure in the downstream fluidic structures.

Fluidic structures, as described with reference to FIGS. 9 to 11 E, may be particularly useful for storing a first fluid in a first fluid chamber of a fluid holding region while a second fluid is undergoing further independent process steps. These process steps can use largely freely required rotational frequencies and temperatures, without the liquid in the first fluid chamber 300 being switched via the liquid guide path 320. After processing, the second liquid may be added to the first fluid chamber 300 and the second fluid chamber 302. The resulting liquid mixture can then be switched by reducing the temperature.

It will be apparent to those skilled in the art that in the described use of negative pressure, the fluid chamber of the fluid holding area may also be divided into three or more chambers. In embodiments, the various chambers of the liquid holding area need not be connected via channels, except for the connection via the downstream fluidic structures and the connection channels connecting the fluid chamber to the downstream fluidic structures.

Generally, in embodiments, the fluid guide path opens at a position into a fluid receiving chamber of the subsequent fluidic structures, which is radially outward of a position at which the fluid guide path opens into a fluid chamber of the fluid retaining region. In other words, the liquid guide path has an overall radial gradient. Thus, it is possible to transfer the liquid from the corresponding chamber of the liquid holding region into the subsequent fluidic structures via a siphon vertex, which is radially inside the mouth of the liquid guide path into the fluid chamber of the liquid via the liquid guide path having a siphon channel Holding area is arranged.

In embodiments, the downstream fluidic structures may include at least one fluid receiving chamber into which the fluid is transferred. When According to exemplary embodiments, the liquid-holding region can have at least one fluid chamber from which the liquid is transferred into the downstream fluidic structures.

In embodiments, the fluidic structures are designed such that centrifugal pressures and pneumatic pressures play a major role, while capillary forces can be negligible. In embodiments, the respective fluid paths may be formed as fluid channels, wherein in the fluid paths chambers, for example, partial compression chambers may be arranged.

Embodiments thus provide fluidic modules, devices and methods in which two fluid communication paths are provided between a chamber in which a liquid is retained prior to switching and a target structure for the liquid after the switching operation. This allows a largely liquid-property-independent monolithic realization of a structure for switching a liquid in the event of selectively exceeding or dropping below a high rotational frequency of the cartridge. Embodiments provide a centrifugal pneumatic venting siphon valve having fluidic structures on a centrifugal test carrier. The fluidic structures may include a first number of chambers, subsequent fluidic structures, and at least two fluid paths connecting the first number of chambers to the subsequent fluidic structures. At least one of the fluid paths between the first plurality of chambers and the subsequent fluidic structures includes a siphon channel, the connection being arranged via the fluid paths from the first plurality of chambers to the subsequent fluidic structures such that when the first plurality of chambers are filled with fluid a state can be produced in which in the subsequent fluidic structures, a gas volume trapped by the liquid is formed or a quasi-enclosed gas volume is produced, in which the following structures have a vent with a venting delay resistance. In embodiments of such fluidic structures, a siphon channel is provided in at least one of the fluid communication paths between the first plurality of chambers and the subsequent fluidic structures, the siphon apex being located radially within the radially outermost position of a first chamber into which the siphon channel terminates. In embodiments of such fluidic structures, the subsequent fluidic structures are not vented. In embodiments, the number of chambers may include one chamber or more than one chamber. Embodiments provide a method for retaining and switching liquids using a corresponding centrifugal pneumatic venting siphon valve, wherein one or more liquids in a liquid holding region (a first number of chambers) in a quasi-static manner dominated by centrifugal pressures and pneumatic pressures Balance is retained / so that a subsequent initiation of a transfer of at least one liquid from the liquid-holding region in the subsequent fluidic structures is possible only by changing the acting centrifugal and / or pneumatic pressures. In embodiments of such a method, in the course of the transfer of liquid from the liquid holding region into the subsequent fluidic structures, gas is transferred from the subsequent fluidic structures in the direction of the liquid holding region via at least one fluid path. In embodiments of such a method, during the transfer of liquid from the liquid-holding region into the subsequent fluidic structures, at least one fluid connection path between the liquid-holding region and the subsequent fluidic structures is not completely filled with liquid. In embodiments of such a method, the molar amount of gas in the subsequent fluidic structures is not changed by a fluid path associated with the environment while retaining liquid in the liquid holding area. In embodiments of such a method, liquid in the liquid holding region is retained in the subsequent fluidic structures due to a pneumatic negative pressure prior to the initiation of the transfer. In embodiments of such a method, liquid in the liquid holding area is retained due to a pneumatic overpressure in the subsequent fluidic structures prior to the initiation of the transfer.

Embodiments may include and are not limited to any modifications and combinations of the illustrated schematic embodiments.

Although features of the embodiments of the invention have been described above by means of a method or apparatus, it is to be understood that the apparatus features described are each features of a corresponding method and the described features also represent features of a corresponding apparatus that may be configured to be one to deliver appropriate functionality. Embodiments of the invention thus provide methods and apparatus for switching fluid using a centrifugal pneumatic venting siphon valve having fluidic structures as described herein. In contrast to the prior art, embodiments of the described structure, in conjunction with the described method in the field of centrifugal microfluidics, can simultaneously meet several requirements for the unit operations of retention and later targeted switching of a liquid. Exemplary embodiments enable a monolithic realization of the associated fluidic structures in a centrifugally microfluidic cartridge. Embodiments offer the possibility of designing the structure, so that the functional principle is largely independent of liquid and cartridge material properties. This includes in particular the contact angle between the liquid and the cartridge material, as well as the viscosity and surface tension of the liquid. Embodiments offer the possibility of further adaptations of the fluidic structures in order to determine the necessary process conditions for triggering a switching process in a wide range. The adaptation possibilities can relate in particular to the possibility of freely selecting the gas volume transferred into the subsequent fluidic structures and the pneumatic overpressure achieved thereby.

Embodiments provide the opportunity to initiate the switching process using various changes in the processing conditions. This includes in particular rotational frequencies, temperatures and waiting times (when using a venting delay resistor) during processing. Embodiments offer the possibility, under recourse to temperature changes as a function of the process control, of switching a liquid above a threshold frequency or below a threshold frequency when the rotational frequency is reduced. Embodiments offer the possibility of producing the microfluidic structures without sharp edges, that is, with low demands on manufacturing processes, such. B. injection molding and injection-compression molding. Embodiments of the invention make it possible to avoid strongly increasing pneumatic pressures in the fluidic target volume during the fluid transfer after the switching operation. Embodiments offer the possibility of cascading the fluidic structures. Finally, embodiments provide the opportunity for multiple use of the fluidic structures to sequentially retain and selectively switch multiple fluids. Embodiments of the invention are configured to change the ratio of the centrifugal pressure to the pneumatic pressure to exceed a threshold at which a siphon apex of the siphon channel in the first fluid path is overcome, such that transfer of the liquid from the liquid holding region takes place in the downstream fluidic structures.

Embodiments of the invention describe variants of the fluidic structures and associated methods, which show various possibilities for influencing the equilibrium of the pressures which act in the direction or contrary to the initiation of the switching process according to the invention. Embodiments of the invention are further based on the recognition that the described switching principle can easily be combined with other operations on the same centrifugal microfluidic platform, for example by passing a liquid after previous fluidic operations in a structure according to the invention or by cascading the described switching structure.

Claims

claims

A fluidic module (50) for switching liquid (80) from a liquid holding region (52, 202, 300, 302) into downstream fluidic structures (58, 94, 158, 210, 322), comprising: a liquid holding region (52, 202, 300, 302), in which a liquid (80) can be introduced, at least two fluid paths (60, 62, 206, 208, 320, 324), the liquid holding region (52, 202, 300, 302 ) fluidically connect to downstream Fluidikstrukturen (58, 94, 158, 210, 322), wherein at least a first fluid path (62, 206, 320) of the two fluid paths having a siphon channel, wherein a Siphonscheitel (64, 212, 326) of the Siphonkanals radially is located within a radially outermost position of the liquid holding portion (52, 202, 300, 302), wherein an inlet and an outlet of the siphon channel are spaced apart from a center of rotation by an entrance than an intermediate portion of the siphon channel and wherein the siphon apex (64, 212, 326 ) an area of the siphon channel with a m minimum distance from the center of rotation, wherein the downstream fluidic structures (58, 94, 158, 210, 322) are not vented or are vented only via a venting delay resistor (66) when the liquid (80) in the liquid holding area ( 52, 202, 300, 302) is introduced, so that in the downstream fluidic structures (58, 94, 158, 210, 322) a trapped gas volume or only via a venting delay resistor (66) vented gas volume is formed when the liquid in the liquid holding region (52, 202, 300, 302) is introduced, and by a ratio of a caused by a rotation of the fluidic module (50) centrifugal pressure and prevailing in the gas volume pneumatic pressure is at least temporarily prevented that the fluid through the fluid paths (60, 62, 206, 208, 320, 324) enters the downstream fluidic structures (58, 94, 158, 210, 322), wherein a change in the ratio of the centrifugal pressure to the pneumatic pressure can cause the liquid to flow at least partially through the first fluid path (62, 206, 320) into the downstream fluidic structures (58, 94, 158, 210, 322) and Gas volume through the second fluid path (60, 208, 324) of the two fluid paths at least partially in the liquid-retaining region (52, 202, 300, 302) is vented.

The fluidic module (50) according to claim 1, wherein the fluid is introduced into a fluid chamber (52, 202, 300) via a centrifugal pressure caused by a rotation of the fluidic module (50) via a radially sloping inlet channel (56, 110, 200, 308, 312). the liquid holding area can be introduced.

The fluidic module (50) of claim 1 or 2, wherein the second fluid path (60, 208, 324) of the two fluid paths is a vent channel for the downstream fluidic structures (58, 94, 158, 210, 322) closed by the fluid when the liquid is introduced into the liquid holding portion (52, 202, 300, 302).

The fluidic module (50) according to any one of claims 1 to 3, wherein the first fluid path (62, 206, 320) opens into the fluid holding region (52, 202, 300, 302) in a radially outer region or a radially outer end, such that the liquid holding region (52, 202, 300, 302) is conveyed via the first fluid path (62, 206, 320) at least to the region in which the first fluid path (62, 206, 320) opens into the liquid holding region ) is emptied.

The fluidic module (50) of any one of claims 1 to 4, wherein the liquid holding region comprises a first fluid chamber (52, 202, 300), the first fluid path (62, 206, 320) being in a radially outer region of the first fluid chamber (5). 52, 202, 300) or at a radially outer end of the first fluid chamber (52, 202, 300) opens into the first fluid chamber (52, 202, 300).

The fluidic module (50) of claim 5, wherein the first fluid chamber (52) is deflated or is vented only via a venting delay resistor when the fluid is introduced into the fluid retaining region such that fluid introduced into the first fluid chamber (52). and the downstream fluidic structures (58, 94) trapped gas volume or only via a venting Delay Resistance Vented gas volume is created when the liquid is introduced into the liquid holding area.

7. fluidic module (50) according to claim 5, wherein the liquid-retaining region further comprises a second fluid chamber (302), in which by a in a rotation of the fluidic module (50) caused centrifugal pressure, a liquid is introduced, wherein the first fluid path (320 ) into the first fluid chamber (300) and the second fluid path (324) into the second fluid chamber (302) opens, and wherein the second fluid path (324) by a in the second fluid chamber (300) introduced liquid is closable.

8. fluidic module (50) according to claim 7, wherein the first fluid chamber (300) and the second fluid chamber (302) via a connecting channel (304) are fluidly connected to each other, the mouth of which in the first fluid chamber (300) radially inward than a radially outer end of the first fluid chamber (300), so that liquid from the first fluid chamber (300) into the second fluid chamber (302) overflows when the level of liquid in the first fluid chamber (300) reaches the mouth, and in the second fluid chamber (302) opening second fluid path (324) closes.

9. fluidic module (50) according to any one of claims 1 to 8, wherein the second fluid path (60, 208, 324) comprises a siphon channel.

10. fluidic module (50) according to claim 9, wherein the second fluid path (208, 324) in a radially outer region of the liquid-retaining region (52, 202, 302) in the liquid-retaining region (52, 202, 302) opens.

The fluidic module (50) of claim 10, wherein a vertex (92, 214, 328) of the siphon channel of the second fluid path (60, 208, 324) is located radially further inward than a vertex (64, 212, 326) of the siphon channel of the siphon channel first fluid path (62, 206, 320).

The fluidic module (50) of claim 10 or 11, wherein in the second fluid path (60) between the apex (92) of the siphon channel of the second fluid path (60) and the mouth (116, 132) of the second fluid path (60) in the fluid holding region (52) is arranged a fluid intermediate chamber (112), wherein the fluid idzwischenkammer (112) is at least partially filled with the liquid when the liquid is introduced into the liquid-retaining region (52).

13. The fluidic module according to claim 1, wherein the downstream fluidic structures have at least one downstream fluid chamber into which the first fluid path opens.

14. The fluidic module (50) according to claim 13, wherein the first fluid path (62, 206) opens radially further out into the downstream fluid chamber (58, 210) than the second fluid path (60, 208).

15. fluidic module (50) according to claim 13 or 14, wherein the downstream fluid chamber (58) is a first downstream fluid chamber and the downstream fluidic structures having a second downstream fluid chamber (94, 158) via at least a third fluid path (96, 160 ) is fluidly connected to the first downstream fluid chamber (58).

16. The fluidic module (50) of claim 15, wherein the first downstream fluid chamber (58) via a third fluid path (160) and a fourth fluid path (162) with the second downstream fluid chamber (158) is fluidly connected, wherein at least the third fluid path (160) has a siphon channel, wherein the third fluid path (160) and the fourth fluid path (162) are closed by the liquid when the liquid is changed by changing the ratio of the centrifugal pressure to the pneumatic pressure through the first fluid path (62) first downstream fluid chamber (58) of the downstream Fluidikstrukturen passes, whereby in the second downstream fluid chamber (158) an enclosed gas volume or vented only via a vent delay resistance gas volume and by a ratio of the centrifugal pressure and in the gas volume in the second downstream fluid chamber (158) prevailing pneumatic pressure ks is at least temporarily prevented that the liquid passes through the fluid paths (160, 162) in the second downstream fluid chamber (158), wherein changing the ratio of the centrifugal pressure to the pneumatic duck in the second downstream fluid chamber (158) may cause the fluid to pass at least partially through the third fluid path (160) into the second downstream fluidic chamber (158) and remove the volume of gas from the second fluidic chamber second downstream fluid chamber (158) through the fourth fluid path (162) is at least partially vented into the liquid-retaining region.

17. A device for switching fluid from a fluid holding area into downstream fluidic structures with a fluidic module (50) according to one of claims 1 to 6, a drive device (20) which is designed to apply a rotation to the fluidic module (50) , and an actuator (20, 24, 40, 42) adapted to effect the change in the ratio of the centrifugal pressure to the pneumatic pressure.

18. The apparatus of claim 17, wherein the actuator (20, 24) is configured to increase or decrease the rotational speed of the fluidic module (50) to effect the change in the ratio of the centrifugal pressure to the pneumatic duck.

19. The apparatus of claim 17 or 18, wherein the actuating means (40, 42) is adapted to the pneumatic pressure in the downstream fluid idikstukturen by reducing the temperature in the downstream fluidic structures, by increasing the volume of the downstream fluidic and / or to reduce a reduction in the amount of gas in the downstream fluidic structures.

20. A method for switching liquid from a liquid holding region (52, 202, 300, 302) into downstream fluidic structures (58, 94, 158, 210, 322) using a fluidic module (50) according to one of claims 1 to 16, with the following features:

Introducing at least one liquid (80) into the liquid holding area (52, 202, 300, 302) and holding the liquid in the liquid holding area (52, 202, 300, 302) by rotating the fluidic module (50) so that the Liquid in a quality dominated by the centrifugal pressure and the pneumatic pressure. si-stationary equilibrium is maintained in the liquid holding portion (52, 202, 300, 302); and

Changing the ratio of the centrifugal pressure to the pneumatic pressure to transfer the fluid at least partially through the first fluid path (62, 206, 320) into the downstream fluidic structures (58, 94, 158, 210, 322) and the gas volume through the second fluid path the two fluid paths at least partially in the liquid-retaining region (52, 202, 300, 302) to vent.

21. The method of claim 20, wherein maintaining the liquid in the liquid holding region (52) comprises generating a pneumatic positive pressure in the downstream fluidic structures (58, 94, 158) prior to initiation of the transfer.

22. The method of claim 21, wherein changing the ratio of the centrifugal pressure to the pneumatic duck comprises increasing the rotational speed of the fluidic module (50), increasing the hydrostatic head of the fluid, and / or decreasing the pneumatic pressure.

23. The method of claim 20, wherein maintaining the liquid in the liquid-holding region comprises generating a negative pressure in the downstream fluidic structures (210, 322), around menisci (102, 104, 122) in the liquid-holding region and the first and adjusting and maintaining the second fluid path (206, 208, 320, 324) without transferring the fluid through the first fluid path (206, 320) into the downstream fluidic structures (210, 322) and changing the ratio of the centrifugal pressure to the pneumatic pressure has a reduction of the rotational speed of the fluidic module (50) and / or a reduction of the pneumatic pressure in the downstream fluidic structures (210, 322).

24. The method of claim 22 or 23, wherein changing the ratio comprises reducing the pneumatic pressure by decreasing the temperature in the downstream fluidic structures (210, 322), increasing the volume of the downstream fluidic structures (210, 322), and / or reducing the amount of gas in the downstream fluidic structures (210, 322).

25. The method of claim 20, wherein during the transfer of the liquid through the first fluid path, the second fluid path is not completely filled with liquid.

26. The method according to any one of claims 20 to 25, wherein the molar amount of the gas in the downstream fluidic structures (58, 94, 158, 210, 322) is not changed, while the liquid in the liquid-retaining region (52, 202, 300 , 302).